In the power generation industry, power generators include high voltage generator stator coil windings. Each winding comprises a plurality of conductive metal strands, each of which may be insulated by a coating. Due to one or more conditions, a strand may have a failure, such as a crack or a break. A crack being a split in the strand without the strand being separate parts whereas a break is when the stand is split into separate parts. Failure of strands can lead to a malfunction of the stator.
A method for detecting a failure of strands or of the winding is a voltage detection test (VDT), which involves conducting a current in a winding and measuring a voltage drop between two points on the winding. A voltage drop in a specified range can be indicative of a failure. The voltage drop may not be sufficient to detect a low number of failures, for example, in a single strand or possibly in a few strands. Additionally, a cracked or broken strand may be in electrical contact at the point of failure allowing current to pass through crack or break. In such a case, the failure would be undetected by the VDT. Furthermore, preparation of the VDT is time consuming drilling holes in the winding in order to conduct the test. In the case the VDT does not detect failure, any holes would be re-plugged after testing. It is possible that the plugs could create a point of future failure.